(a) Field of the Invention
The present invention relates to a driving wheel series in which reciprocal treadle performed by human's two feet is transformed into rotation motions, especially one or both of an active wheel and a passive wheel is composed of an eccentric transmission wheel and combined with a synchronous transmission belt for forming an eccentric wheel transmission wheel series, so that in the reciprocal treadle performed by the rider's feet, through the certain structure of treadle-drive eccentric wheel transmission wheel series with periodically varied speed ratio to incorporate with the certain relation with respect to the treadling angle, the active wheel generates two speed ratio variations to the passive wheel in each rotation period, thereby by incorporating with the reciprocal treadle performed by two feet, when the feet input forces at different angles from the treadle shafts of the treadles to an active wheel shaft combined on the active wheel through cranks, the active wheel forms different transmission speed ratios relative to the passive wheel.
(b) Description of the Prior Art
A conventional treadle-drive transmission wheel series in which reciprocal treadle are performed by human's two feet is often utilized in an appliance wherein the reciprocal treadle performed by two feet is adopted for generating the rotation driving, such as a human treadling driven bicycle, a movement-assisting bicycle with human treadling drive and an electric motor for assistance, a fixed bicycle for exercising, a treadle-drive boat, a treadle-drive rotation type power generator, or a treadle-drive rotation fluid pump; in a treadle-drive transmission wheel series, chain wheels incorporate with chains, belt pulleys incorporate with belts, timing belt pulleys incorporate with timing belts, gears incorporate with tooth-shaped chains or gear transmission sets, so two feet can treadle a round active wheel for linking a passive wheel for driving a load; in the treadling, the feet can apply the most efficient treadling force to the active wheel with a certain angle displacement range, but the reciprocal treadle performed by human's feet and the rotation motion of the active wheel form a relation of simple harmonic motion, and due to the relation of simple harmonic motion, inefficient or low-efficient angle displacement ranges still exist and shall be improved.